Morphological Stability of a Particle Growing by Diffusion or Heat Flow

Mullins, W. W.; Sekerka, Robert F.

doi:10.1063/1.1702607

Cited by 1,887 publications

(628 citation statements)

References 4 publications

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“…Alloys with low lattice misfits may form precipitates with such morphologies as a result of diffusion-induced interface instabilities. [33,34] In contrast, in alloys with larger misfits, the process is governed almost entirely by the strain energy. [31] Evidence of this process was observed in the microstructure after aging for 100 hours, Figure 1(i).…”

Section: A Precipitate Morphologymentioning

confidence: 99%

Gamma Prime Precipitate Evolution During Aging of a Model Nickel-Based Superalloy

Goodfellow

Galindo-Nava

Christofidou

et al. 2017

Metall Mater Trans A

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The microstructural stability of nickel-based superalloys is critical for maintaining alloy performance during service in gas turbine engines. In this study, the precipitate evolution in a model polycrystalline Ni-based superalloy during aging to 1000 hours has been studied via transmission electron microscopy, atom probe tomography, and neutron diffraction. Variations in phase composition and precipitate morphology, size, and volume fraction were observed during aging, while the constrained lattice misfit remained constant at approximately zero. The experimental composition of the γ matrix phase was consistent with thermodynamic equilibrium predictions, while significant differences were identified between the experimental and predicted results from the γ′ phase. These results have implications for the evolution of mechanical properties in service and their prediction using modeling methods.

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Section: A Precipitate Morphologymentioning

confidence: 99%

Gamma Prime Precipitate Evolution During Aging of a Model Nickel-Based Superalloy

Goodfellow

Galindo-Nava

Christofidou

et al. 2017

Metall Mater Trans A

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“…Due to a high strength of Cr-rich phase, the eutectic part has higher strength than matrix. Eutectic with fiber shape can reinforce the copper matrix in direction parallel to these fibriform microstructures and keep a good conductivity [3]. However, it should be noticed that most of the previous researches mainly focus on the effect of the microstructure of the unidirectional solidified Cu-Cr alloys on conductivity [4,5].…”

Section: Introductionmentioning

confidence: 99%

Interface morphology evolvement and microstructure characteristics of hypoeutectic Cu–1.0 wt%Cr alloy during unidirectional solidification

Hu¹,

Xiao-qin

et al. 2005

Science and Technology of Advanced Materials

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Effect of unidirectional solidification rate on microstructure of hypoeutectic Cu-1.0%Cr alloy was investigated. The microstructure evolution of Cu-1.0%Cr alloy was noticed especially during the unidirectional solidification with the different solidification rates. It is shown that eutectic (aCb) and primary a(Cu) phase grew up equably in parallel to direction of solidification. A kind of fibriform microstructure will appear when unidirectional solidification rate is up to some enough high certain values. When temperature gradient was changeless, the interface morphology evolution of the primary a(Cu) phase underwent to a series of changes from plane to cell, coarse dendrite, and fine dendrite grains with increasing the solidification rates. Primary dendrite arm spacing l1 of a(Cu) phase increases with increasing the solidification rate where the morphology of the solid/liquid (S/L) interface is cellular. However, l1 decreases with further increasing the solidification rate where the S/L interface morphology is changed from cell to dendrite-type. Its rule might accord with Jackson-Hunt theory model. An experience equation obtained is as follows:On the other hand, secondary dendrite spacing l2 of primary a(Cu) phase will thin gradually with increasing the solidification rate. Moreover, secondary dendrite will become coarse in further solidification. Another experience equation about relationship among secondary dendrite arm spacing (l 2 ), temperature gradient G L and the velocity of the S/L interface (V) is that: l 2 ZK0:0003C 0:0027ðG L VÞ K1=3 . In addition, the volume fraction of eutectic will decrease with the increase of solidification rate. q

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“…A mushy layer separates the region occupied by the completely solidified material from that occupied by the melt phase. Mushy layers may form as a result of the morphological instability of a solidification front [19] and occur frequently during the solidification of binary and ternary alloys [3]. The presence of a mushy layer during solidification can greatly influence the transport of heat, mass and solute, and therefore the final solidified product.…”

Section: Steady Statesmentioning

confidence: 99%

Front propagation in a phase field model with phase-dependent heat absorption

Blyuss

Ashwin

Wright

et al. 2006

Physica D: Nonlinear Phenomena

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We present a model for the spatio-temporal behaviour of films exposed to radiative heating, where the film can change reversibly between amorphous (glassy) and crystalline states. Such phase change materials are used extensively in read-write optical disk technology.In cases where the heat absorption of the crystal phase is less than that in the amorphous state we find that there is a bi-stability of the phases. We investigate the spatial behaviours that are a consequence of this property and use a phase field model for the spatio-temporal dynamics in which the phase variable is coupled to a suitable temperature field. It is shown that travelling wave solutions of the system are possible and, depending on the precise system parameters, these waves can take a range of forms and velocities. Some examples of possible dynamical behaviours are discussed and we show, in particular, that the waves may collide and annihilate. The longitudinal and transverse stability of the travelling waves are examined using an Evans function method which suggests that the fronts are stable structures.

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Morphological Stability of a Particle Growing by Diffusion or Heat Flow

Cited by 1,887 publications

References 4 publications

Gamma Prime Precipitate Evolution During Aging of a Model Nickel-Based Superalloy

Gamma Prime Precipitate Evolution During Aging of a Model Nickel-Based Superalloy

Interface morphology evolvement and microstructure characteristics of hypoeutectic Cu–1.0 wt%Cr alloy during unidirectional solidification

Front propagation in a phase field model with phase-dependent heat absorption

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